That is odd. Might be some issues with files then. Might be worth checking the Aston's .gen file compared to the other's to see if there are any numbers that are off.
For the Aston (excerpt)
//------------------------------------MAX CAR SETTINGS---------------------------------------------
<MAX> MeshFile=vantage_gte_body_loda.GMT CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(15.00) ShadowReceiver=True
<MAX> MeshFile=vantage_gte_body_lodb.GMT CollTarget=False HATTarget=False LODIn=(15.0) LODOut=(50.00) ShadowReceiver=True
<MAX> MeshFile=vantage_gte_body_lodc.GMT CollTarget=False HATTarget=False LODIn=(50.0) LODOut=(100.00) ShadowReceiver=True
<MAX> MeshFile=vantage_gte_body_lodd.GMT CollTarget=False HATTarget=False LODIn=(100.0) LODOut=(350.00) ShadowReceiver=True
//------------------------------------HIGH CAR SETTINGS--------------------------------------------
<HIGH> MeshFile=vantage_gte_body_loda.GMT CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(10.00) ShadowReceiver=True
<HIGH> MeshFile=vantage_gte_body_lodb.GMT CollTarget=False HATTarget=False LODIn=(10.0) LODOut=(40.00) ShadowReceiver=True
<HIGH> MeshFile=vantage_gte_body_lodc.GMT CollTarget=False HATTarget=False LODIn=(40.0) LODOut=(80.00) ShadowReceiver=True
<HIGH> MeshFile=vantage_gte_body_lodd.GMT CollTarget=False HATTarget=False LODIn=(80.0) LODOut=(350.00) ShadowReceiver=True
//------------------------------------MED CAR SETTINGS---------------------------------------------
<MED> MeshFile=vantage_gte_body_loda.GMT CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(40.00) ShadowReceiver=True
<MED> MeshFile=vantage_gte_body_lodb.GMT CollTarget=False HATTarget=False LODIn=(40.0) LODOut=(80.00) ShadowReceiver=True
<MED> MeshFile=vantage_gte_body_lodd.GMT CollTarget=False HATTarget=False LODIn=(80.0) LODOut=(350.00) ShadowReceiver=True
//------------------------------------LOW CAR SETTINGS---------------------------------------------
<LOW> MeshFile=vantage_gte_body_lodb.GMT CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(30.00) ShadowReceiver=True
<LOW> MeshFile=vantage_gte_body_lodc.GMT CollTarget=False HATTarget=False LODIn=(30.0) LODOut=(80.00) ShadowReceiver=True
<LOW> MeshFile=vantage_gte_body_lodd.GMT CollTarget=False HATTarget=False LODIn=(80.0) LODOut=(350.00) ShadowReceiver=True
MeshFile=vantage_gte_interior_loda.GMT CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(15.0) ShadowReceiver=True
MeshFile=vantage_gte_interior_lodb.GMT CollTarget=False HATTarget=False LODIn=(15.0) LODOut=(200.0) ShadowReceiver=True
Corvette (as an example)
Instance=SLOT<ID>
{
Moveable=True
//------------------------------------MAX CAR SETTINGS---------------------------------------------
<MAX> MeshFile=c7r_body_loda.gmt CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(15.0) ShadowReceiver=True
<MAX> MeshFile=c7r_body_lodb.gmt CollTarget=False HATTarget=False LODIn=(15.0) LODOut=(50.0) ShadowReceiver=True
<MAX> MeshFile=c7r_body_lodc.gmt CollTarget=False HATTarget=False LODIn=(50.0) LODOut=(100.0) ShadowReceiver=True
<MAX> MeshFile=c7r_body_lodd.gmt CollTarget=False HATTarget=False LODIn=(100.0) LODOut=(300.0) ShadowReceiver=True
//------------------------------------HIGH CAR SETTINGS--------------------------------------------
<HIGH> MeshFile=c7r_body_loda.gmt CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(10.0) ShadowReceiver=True
<HIGH> MeshFile=c7r_body_lodb.gmt CollTarget=False HATTarget=False LODIn=(10.0) LODOut=(50.0) ShadowReceiver=True
<HIGH> MeshFile=c7r_body_lodd.gmt CollTarget=False HATTarget=False LODIn=(50.0) LODOut=(350.0) ShadowReceiver=True
//------------------------------------MED CAR SETTINGS---------------------------------------------
<MED> MeshFile=c7r_body_loda.gmt CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(10.0) ShadowReceiver=True
<MED> MeshFile=c7r_body_lodb.gmt CollTarget=False HATTarget=False LODIn=(10.0) LODOut=(50.0) ShadowReceiver=True
<MED> MeshFile=c7r_body_lodd.gmt CollTarget=False HATTarget=False LODIn=(50.0) LODOut=(350.0) ShadowReceiver=True
//------------------------------------LOW CAR SETTINGS---------------------------------------------
<LOW> MeshFile=c7r_body_lodb.gmt CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(10.0) ShadowReceiver=True
<LOW> MeshFile=c7r_body_lodd.gmt CollTarget=False HATTarget=False LODIn=(10.0) LODOut=(350.0) ShadowReceiver=True
MeshFile=c7r_interior_loda.gmt CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(200.0) ShadowReceiver=True
MeshFile=Corvette_C7-R_aero_<1>.gmt CollTarget=False HATTarget=False LODIn=(0.0) LODOut=(250.0) ShadowReceiver=True